Milicry

Overview

Executive Summary

Infection Vector and Encryption Mechanics

• Pre-Encryption Evasion: Milicry typically attempts to disable local antivirus services and delete Volume Shadow Copies (`vssadmin.exe Delete Shadows /All /Quiet`) to prevent easy recovery of the encrypted files.
• Data Encryption: The malware scans local drives and mapped network shares for specific file extensions (documents, databases, images, archives). It utilizes a robust combination of symmetric (e.g., AES) and asymmetric (e.g., RSA) cryptography. The encrypted files are typically appended with a specific, recognizable extension (often related to the malware's name or a random string).
• Extortion: After encryption is complete, Milicry drops a ransom note (usually a `.txt` or `.html` file) in every affected directory and often changes the desktop wallpaper. The note provides instructions for paying the ransom in cryptocurrency (usually Bitcoin) to obtain the decryption key.

Threat Assessment

Remediation and Eradication

• Immediate Network Isolation: The infected host must be immediately disconnected from the LAN and Wi-Fi to halt the encryption of mapped network shares and sever communication with the attacker's C2 infrastructure.
• Do Not Pay: Paying the ransom funds criminal enterprises and does not guarantee data recovery. Organizations should check resources like the "No More Ransom" project to see if a free decryptor has been released for the specific Milicry variant encountered.
• Restore from Backup: The most reliable recovery method is to wipe the infected system completely, reinstall the operating system, and restore data from a clean, offline, immutable backup.

Known aliases

Threat reports may refer to this family under multiple names:

• Trojan-Ransom.Win32.Milicry
• Ransom:Win32/Milicry

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1059: Restrict execution of scripting languages such as PowerShell, VBScript, or Python to authorized administrators. Enforce Script Block Logging.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

Tiered Detection Rules (Cisco CAIRN Model)

Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:

rule MALWARE_WIN_MILICRY_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Milicry"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "milicry" ascii wide nocase
        $s2 = "trojan-ransom.win32.milicry" ascii wide nocase
        $s3 = "ransom:win32/milicry" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Milicry (Ransomware) Execution & Triage
id: 01df30cc-b31b-51da-8491-b87930e0759b
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Milicry malware family. Detects volume shadow copy deletion, boot status
  tampering, and recovery inhibition characteristic of modern ransomware operations.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/milicry
- https://malware-families-catalog.systemhelpdesk.com/defensive/ransomware-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.ransomware
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1486
- attack.t1490
- attack.t1059
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \vssadmin.exe
    - \wmic.exe
    - \wbadmin.exe
    - \bcdedit.exe
    CommandLine|contains:
    - delete shadows
    - shadowcopy delete
    - resize shadowstorage
    - recoveryenabled no
    - ignoreallfailures
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: critical

rule MALWARE_WIN_MILICRY_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Milicry tradecraft"
        tier = "T3 - Attribution Fingerprint"
        confidence = "High (Confirmed Family Signature)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        // Core family identifier & heuristic payload signatures
        $attrib_str = "milicry" ascii wide nocase
        $pe_magic = "MZ" ascii
        $net_marker = "http" ascii nocase
    condition:
        uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Immediately isolate affected host(s) from the internal network (disconnect physical Ethernet and disable Wi-Fi/Bluetooth) to prevent Milicry from spreading laterally or encrypting network-attached storage (NAS) and shared SMB volumes.
2. Preserve volatile system memory (RAM capture) on a representative endpoint before attempting a reboot or power-down, as Milicry symmetric encryption keys or uncompiled payload components may still reside in memory.
3. Audit process execution logs and terminate active scripting interpreters (e.g. PowerShell, CMD, WScript) or commands executing 'vssadmin.exe delete shadows' or 'wbadmin' used by Milicry to inhibit recovery.
4. Investigate the initial compromise vector (such as exposed RDP instances, spearphishing attachments, or vulnerable edge gateways) and enforce an immediate credential reset for all compromised Active Directory accounts.
5. Restore critical assets and databases exclusively from verified, air-gapped, or immutable offline backups once the Milicry binary and related persistence hooks are eradicated.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not restart or power cycle infected systems prematurely; doing so destroys volatile RAM encryption keys and may trigger bootloader locking logic embedded in Milicry.
2. Avoid negotiating or paying the extortion demand without prior forensic evaluation and consultation with incident response specialists, as payment does not guarantee data recovery.
3. Do not connect clean backup drives or external storage to the affected network until Milicry eradication is completely verified.

References & External Analysis

• Search "milicry" on VirusTotal (External Analysis)
• Search "milicry" on Any.Run (Sandbox Sandbox)
• Search "milicry" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Ransomware)

Explore other documented threats in the same operational category:

• Fakefolder
• Datakeeper
• Vake
• Msildrop
• Tomegun
• Genericrxdt
• Jaike
• Hamaetot

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/milicry.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.